What is “adultery?”

Strictly speaking, adultery is a sexual relationship between a married person and someone other than his or her spouse.

In the Sermon on the Mount, Jesus expands the definition: “You have heard that it was said to those of old, ‘You shall not commit adultery.’ But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart.” According to Jesus, any man (married, or not) who looks at a woman (married, or not) and thinks about having sex with her, is just as guilty of adultery as the married man who actually does have sex with a woman other than his wife. Although not specifically stated here, the opposite is presumed true as well: A woman who lusts after a man is guilty of adultery as well.

Using Jesus’ definition, almost every person past the age of puberty is guilty of adultery. It is the very rare individual who has never lusted after someone to whom they are not married.

What about other sexual sins?

In addition to adultery, both the Old and New Testaments describe many examples of sexual sins, including (but not limited to):

Additionally, there are a number of New Testament passages warning against the sin of πορνείᾳ, which is translated in various English versions as fornication, unchastity, or sexual immorality. According to Strong’s Concordance, πορνείᾳ – pronounced (por-ni’-ah) – is “a selling off (surrendering) of sexual purity; promiscuity of any (every) type.” πορνείᾳ is the root word for the English word “pornography.” Essentially, πορνείᾳ includes all sexual acts outside of Biblical marriage.

How does the Bible define Marriage?

The basic definition of marriage is found in Genesis 2:24: “Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh.” Jesus reiterated this basic definition in Mark 10:6-8:

6 But from the beginning of the creation, God ‘made them male and female.’ 7 ‘For this reason a man shall leave his father and mother and be joined to his wife, 8 and the two shall become one flesh’; so then they are no longer two, but one flesh.

Both Genesis 2:24 and Jesus define marriage as being between one man and one woman.

What about polygamy? The Old Testament certainly records many instances of polygamous marriages, including Abraham, Jacob, David, and Solomon. However, in each of these cases, polygamous marriages caused serious consequences. Although there are a handful of Old Testament verses that can be interpreted to endorse or even require polygamous marriage, these same verses have also been interpreted to refer to successive marriages, rather than concurrent ones. Regardless of the interpretation of these verses, marrying multiple wives is not in harmony with God’s design for marriage from the beginning.

The same can be said for divorce. There are several Old Testament passages describing procedures for divorce. However, in the same passage from Mark 10, Jesus states that the law allows for divorce because of the hardness of the human heart (verse 5), and that ““Whoever divorces his wife and marries another commits adultery against her. And if a woman divorces her husband and marries another, she commits adultery” (verses 11-12). Again, divorce is clearly not part of God’s design for marriage.

Homosexual marriage is never mentioned in Scripture. However, since the Bible speaks clearly about the sin of homosexuality, and since Jesus defined marriage in terms on one man and one woman, gay marriage is clearly not part of the Biblical design for marriage.

A Christian Response

The Biblical definition for marriage is one man and one woman for life. Divorce, polygamy, and gay marriage are sin, and not part of God’s design. However, all of these are practiced in our culture, even among professing Christians. How should Christians respond?

First, we must not compromise the truth of God’s Word. We need to acknowledge that all sexual relations outside of monogamous, heterosexual marriage are sin. As Christians, we must never compromise the truth of God’s Word.

Second, we also need to remember that “allhavesinned and fall short of the glory of God” (Romans 3:23). By Jesus’ definition, almost every adult is guilty of sexual sin. Christians have no right to judge the sin of others if they do not recognize and repent of their own sin. Just because I haven’t actually had a sexual relationship outside of marriage, I’ve certainly thought about it, so according to Jesus, I’m also guilty. I’ve certainly also committed many other kinds of sin. Christians have no business looking down on the sins of others, just because they haven’t committed those particular sins. We have more than enough sins of our own, without adding hypocrisy to the list.

Christians who are caught in the snare of sexual sin need grace and truth to be able to repent of those sins and be restored to fellowship with Jesus Christ. If married, both the one adulterer and their spouse need compassion and Godly counsel in order to heal the relationship. If in an unbiblical relationship, they need to separate, in accordance to God’s Word, and need to repent of sin.

In the case of non-believers, what they need is the grace of Jesus Christ, not hate from Christians. Christians can, and must, truly hate the sin, but love the sinner. All non-Christians, regardless of whatever sin they may be involved in, need to understand they are sinners, but that Jesus Christ offers salvation and the forgiveness of sin for those who repent and turn to Him.

The following quote has been attributed to both Duck Dynasty’s Phil Robertson and Pastor Rick Warren (I think Warren is the actual source):

“Our culture has accepted two huge lies. The first is that if you disagree with someone’s lifestyle, you must fear or hate them. The second is that to love someone means you agree with everything they believe or do. Both are nonsense. You don’t have to compromise convictions to be compassionate.”

Christians must stand firm on the truth of God’s Word in regards to sexual sin, but at the same time, must demonstrate Christ-like grace and compassion toward sinners. Our goal must be to allow God to work through us to lead sinners to repentance and faith in Jesus Christ.